Bucking bar and support



June 5, 1945- A. H. HABERSTUMP BUCKING BAR AND SUPPORT Filed Jan. 4, 1945 Patented June 5, 1945 UNITED STATES PATENT OFFICE 2,377,416 BUCKING BAR. AND SUPPORT Alfred H. Haberstump, Detroit, Mich., assignor to The Murray Corporation of America Detroit, Mich., a corporation of Delaware Application January 4, 1943, Serial No. 471,236

6 Claims.

This invention relates to bucking bars, and particularly to new and novel means for supporting and applying resilient pressure to a bucking bar which spans a plurality of rivets which are to be swaged seriatim.

In the copending application of Alfred H. Haberstump, Serial No. 413,764, filed October 6, 1941, and assigned to the assignee of the present invention, bucking bar of various types are illustrated, described and claimed. These bucking bars may be attached to elements to be riveted together by clamping means, or are supported on standards on which the pieces to beriveted together are secured. Where the particular workpieces to be riveted do not lend themselves for supporting the bucking bar on the clamps therewith, or where standards cannot be employed for supporting both the bucking bar and the workpieces, the present invention, embodying a unique support for the bar, has application.

The bucking bar proper is mounted on a pair of links which are pivoted to a base member, all of which are in parallelogram relation to each other. Rubber elements extend through the base member in position to be engaged by the links to provide a resilient pressure thereto. Arms extend from both sides of the base member and are projected upwardly for supporting vacuum cups in position to engage the under side of a sheet to be riveted. By forcing the cups against the surface of the sheet, a, holding force is produced which retains the bar against the sheet with a predetermined resilient pressure. A plurality of rivets which are to be swaged are insertable in apertures which are aligned With the bar. A downward pressure is applied to a percussion hammer to force the rivet head into engagement with the sheet and to deflect the bucking bar against the rubber elements supported by the base member. When the hammer is operated, the reaction of the bucking bar swages the rivet end and forms a bucktail of desired height and diameter when a predetermined number of strokes of the hammer have been applied. A timing device,

such as that illustrated and described in the co pending application of Alfred H. Haberstump, Serial No. 439,115, filed April 15, 1942, and assigned to the assignee of the present invention, may be employed for accurately timing the number of strokes for each cycle of operation.

It is within the purview of the invention to apply a vacuum line to the suction cups to produce a greater vacuum and holding force when only small cups can be employed, which would not provide sufiicient holding force for the bar.

Accordingly, the main objects of the invention are: to support a bucking bar on the arm ofa base member having vacuum cups on the end which engage the sheet to be riveted; to project arms on a base member of a bucking bar upwardly on which vacuum cups are supported below the top of the bar to form a support therefor with the bar in engagement with the under surface of the element to be riveted; to construct a, bucking bar from a base member formed of spaced elements between which links are pivoted and disposed to rest upon rubber elements extending through the elements for applying a resilient pressure to a bucking element which is pivoted on the ends of the links; to support a bucking bar on hollow arms which have vacuum cups on the ends thereof connected to a source of vacuum for providing a support for the bar on the elements to be riveted; and, in general, to form a bucking bar and a support therefor which is simple in construction, positive in operation, and economical of manufacture.

Other objects and features of novelty of this invention will either be specifically pointed out or will become apparent when referring, for a better understanding of the invention, to the following description, taken in conjunction with the accompanying drawing, wherein:

Figure 1 is a view in elevation of a bucking bar and a support therefor embodying features of this invention;

Fig. 2 is an endview of the structure illustrated in Fig. 1;

. Fig. 3is an enlarged sectional view of the structure illustrated in Fig. 1, taken on the line 3-3 thereof; and

Fig. 4 is an enlarged view, partly in section, of structure, similar to that illustrated in Fig. 2, showing a modified form thereof.

The bucking bar l0 embodies a base element It made of side members [2 and I3 which are mounted in spaced relation by a pair of blocks l4. Between the elements l2 and [3, links I5 are mounted on pivots H5. The opposite ends of the links are secured to the bucking element IT by pivots l8.

Recesses [9 are provided in the under side of the bucking element for receiving the ends of the links I5. Rubber elements 2|, having round body portions 22, extend through annular apertures 23 in the side members I 2 and [3 in position to engage the links l5 when the bucking element I1 is in raised position. Square ends 24 on the rubber elements 22 extend over the outside of the side members I2 and I3 for retaining the rubber elements in position. outwardly extending, upwardly projecting arms 25 are provided on each side of the members I2 and I3 near each end thereof for supporting vacuum cups 26 which are secured to the end of the elements 25 by screws 21.

It will be noted, from Figs. 1 and 2, that the bucking element IT projects above the cups 26 when the links lS-rest upon'the:rubber:elements 21 so as to'have the 'bucking element deflected against the rubber elements when the vacuum cups 26 are secured against the under side of "a sheet of metal to be riveted. This'providesa predetermined resilient pressure to the bucking element which will be suflicient to-produce a reaction on the ends of the rivets when they are struck by the percussion hammer'to produce -the swaging operation. This eliminates "the hazard of having too great a pressure applied to the bucking element H, which would react-upon'the .cups 26 :to :weaken .the holding ;force .thereof and release .the bar. from-the-sheet.

.The parallelogram:arrangement-ofithe.bucking element l l witlrtheibaseelement L and. the pair .of parallel links l produces-a transverse supportfor' the bucking-element which will have-all points throughout the .lengthof .the bar react in thesame manner-,onra rivet. .Llkehucktailswill be swaged'on'the rivet ends upon theapplication of .a; predetermined number f -.blows..of the mer- ;oussion-hammeroneach of therivets. .Thiselimi- -.nates the examination and .the-restriking of.- the rivets :which occurs when an..individual .manually supportera buckingbaragainst the-rivet ends.

.=In:Fig. 4 a slightly modifieddonn obbucking bar is illustrated, that wherein .the zoutwardly and ,upwardly-projectingmlements :28 are .hollow tubes to which a-e0nductor-3I .is joined .for.-sup- ,plyingza vacuumsuction tO'ICllD-Sc32 securedto the .end'of the elements-29. iberemployed 40 when small cups must :be employed which would not have sufficient strength to suppontathetbar-by against the .sheet of .material .33. The .application of 2a rivet .to the :bar 1 is illustrated, with the .bar deflected -,by .the .rivet when .the percussion ,hammer :34 is-forced. downwardly againstthe rivet head to move thehead against the top surface *Of thezsheet '35. .Thadefiection ,of.1;he.bar radds additional .resilient ,pressure thereto which -retains the bar against the rivet end 'as the-.end

1isswage'd by the operation oftthe percussion 'hammer on the rivet head to form the bucktailaon .the

rivet tend. ,Thelbucking zbarsxillustrated'in the I LfiglllEES .=are::ruggedt-in constructioniand positively retained in position to engage the'rivets tobe =swaged. It: is to-be understood that theibar may beaof any shape-conforming 'to'the straight or curved line in whichthe rivets'are disposed and has the top face positioned so as to be normal to the axis of the rivets to produce bucktails having their axes aligned with the axes of the rivets.

What is claimed is:

l. A bucking bar, including, in combination, a base element, a pair of links supported on the base element, a bucking element supported on the ends of the links, supporting means on the .base elementby which thebase element is supported with'the bucking element in position to engage a plurality of rivets to be swaged, and

*vacuum cups attached to the supporting means 4a avacuum .caused .by {the deflection got the .cup

,forcsecuring the supporting means in position.

2. A bucking bar, including, in combination,

a base element, a pair of links pivoted on said *baseelementna bucking element pivoted on said links, resilient means supported by said base element;in aengagement with said links for urgin said links to move the bucking element toward 'therivet to be swaged, arms on said base element,

-.and vacuum cups .on .said arms ,for supporting .said bucking bar I in position to engage :the ends ofaplurality. of rivets :tobe swaged.

3. Abucking :bar, including, in combination, a pair of spaced elements, linksypivoted between said elements, resilientmeans supported by said elements with which the links' engage for urging said :links to :move -,the .bucking element toward the;rivets to be-.swaged,'aupwardly projecting: arms secured -to said spaced elements, vacuum @cups supportedonthe ends of said arms, and a bucking .elementmivotally supportedon the ends'of said links.

-.4. In a bucking bar, a 'base' elementrembodying .apair of members secured in ispaced-apart-relation, a pair of links pivoted between said members, rubber elements .projecting across said members in position to engagesaid links, a bucking bar 'pivoted to the ends of said links, upwardly projecting arms .onsaid base member, and-vacuum cups supported on the ends of .said

arms.

.5. -A bucking banincluding, in combination, a

base-,element,;links pivoted :on. said base element, a bucking element pivoted to the ends of .said .links, tubular elements projecting upwardly from the base element, vacuum cups supported on the ends of the tubular elements, and a conduit joined to said-tubularelements.

'6. Ina-bucking bar, an'elongated-base element,

-a bucking elementof a length to engage a plurality of rivets mounted for movement toward and iromsaid base element, means for applying a resilient pressure between 'said base element 1 and-saidbucking element, and'vacuum means f or supporting the base :element with the bucking elementin position'to'engagethe ends of a plurality of rivets to be'swaged.

ALFRED H. 

